Effects of dietary rainbow trout (Oncorhynchus mykiss) viscera protein hydrolysate on some hematological and blood serum biochemical parameters of rainbow trout juvenile

The aim of this study was to prepare rainbow trout (Oncorhynchus mykiss) visceral protein hydrolysate (VPH), determine the peptide molecular weight and using rainbow trout visceral protein hydrolysate in diet of rainbow trout juvenile to investigate its effects on some hematological and blood serum biochemical parameters. The viscera of rainbow trout were hydrolyzed by alcalase enzyme and Antioxidant activity of protein hydrolysate was obtained 85±1.6 %. The protein hydrolysate was used for the second phase of the experiment. For this purpose, four diets were prepared including VPH free as the control and three diets with 0.5, 1, and 2 percent VPH inclusions. Juvenile rainbow trout (n = 252; 9.74 ± 0.22 g) were randomly distributed in the treatments (with three replicates) and fed with the prepared diets based on satiation, 3 times a day for 60 days. Peptide polecular weight ranged from 700 D to 2 KD. Final evaluated parameters were hematological (RBC, hemoglobin, hematocrit, WBC, MCV, MCH and MCHC), serum biochemical (total protein, albumin, glucose, cholesterol and triglyseride) indices and lysosyme. Increasing the VPH up to 2 % caused to increase hemoglobin (P<0.05). RBC and WBC showed no significant differences among treatments (P>0.05).  The lowest hematocrit was observed in 1 % treatment (P<0.05). The highest amounts of albumin and cholesterol were observed in 2 % treatment and the highest amount triglyseride and the lowest amount of glucose were observed in control group (P<0.05).  All VPH-containing treatments had higher amount Lysosyme activity than control as such with inceasing VPH up to 2 % coused to increase the lysosyme activity and the lowest amount of that was observed in control (P<0.05). The results indicate that a diet containing 2 % of VPH cause to affect on some mentioned haemetological and serum biochemical parameters and could improve immunity in in juvenile rainbow trout.